This invention relates to an offset perfecting press comprising a first rubber cylinder, a first plate cylinder, a second rubber cylinder serving also as an impression cylinder, and a second plate cylinder.
This perfecting press has a smaller number of cylinders, and is simpler and more compact in construction than any conventional combination of two presses each having a rubber cylinder, a plate cylinder and an impression cylinder.
Perfecting presses of this type, however, have common problems which are due to the simultaneous printing on both sides of paper disposed between the first and second rubber cylinders. The adjustment of images on both sides of the paper is very troublesome and difficult. Many complications and difficulties are involved in the movement of the cylinders toward and away from one another, plate feeding and discharge, moistening, inking, blanket cleaning and other operations, and in the selective operation for printing on one or both sides of the paper.